deer are unpredictable unless it's spine or brain. Last year, i shot a doe at 30 yards, hit her tight behind the shoulder, got both lungs and the top of the heart, sprayed blood 3 feet on both sides of the trail, but she still ran 35 yards. i had the same exact hit on my buck this year, and he ran 40 yards. i've shot some does with the same loads and most drop as if hit by lightning. i've heard in some articles about it depends on the heartbeat when you hit it, kinetic energy, fast velocity(Roy Weatherby), big calibers, everything..i just aim on the shoulder hoping to break it, but anywhere in the frontal chest cavity and that deer is gonna park himself in the near vicinity.